The overall objective of the research is to continue epidemiological studies related to three major themes on substance use in adolescence and adulthood: (1) the natural history of involvement in drugs, (2) the risk factors for using drugs, and (3) the consequences of using drugs. Risks and consequences include mental health, behavioral, interpersonal and intrapersonal factors. The drugs under consideration include cigarettes, alcohol, illicit drugs, especially marijuana and cocaine, and medically prescribed psychoactives. Most of my work to date has been carried out on cross-sectional school- based samples of adolescents and long-term longitudinal follow-ups of youths from adolescence to adulthood. During the period of requested support, the research will be extended in several directions with respect to the populations and the drug behaviors being studied: (a) The consequences of interest are broadened to include consequences for the user's family (spouses and children) in addition to consequences for the individual users; (b) the epidemiology is extended from school-based samples to the hard-to-reach population of school dropouts; (c) the drug behaviors of interest are expanded to include those related to diagnosed cases of substance abuse in addition to the traditional quantity/frequency measures used in epidemiological drug research. Three interrelated programs of research will be pursued to achieve these aims: (1) an investigation of the intergenerational consequences of drug use in a longitudinal cohort of 1,160 adults who have been studied since 1971 and were reinterviewed in 1990 at age 34, their spouses or partners, up to 2 children 9-17 years old, and teachers. (2) a projected prospective longitudinal study of the epidemiology of drug use among school dropouts compared to non-dropouts and the risk factors for dropping out at various points throughout high school. An initial school-based survey will be carried out on a representative probability sample of 43,700 school students in 107 public intermediate and senior high schools in New York City. Sixteen months later, all school dropouts (N=3,000 completed cases) and an equal number of in-school students will be followed. At Wave 1, data will also be obtained from 25% of parents and all school principals. (3) Participation in a larger project, a multi-site collaborative program of methodological studies, which will develop instruments and methods to measure childhood psychopathology, risk factors for psychopathology, and mental health service utilization in children aged 9-17. Together, this program of research will address within a lifespan perspective issues of crucial importance for understanding the epidemiology of drug use among young people, the risk factors, and the effects of drug use for young people and their families.